Because at first the hate received by gays in the form of homophobia was due to gender nonconformity within a conservative and right wing society. Effeminate gay men got it worse because 1 they couldn't hide and 2 they more clearly violated the gender rules which all gays violated by refusing to get married and have 2.5 children. If you look at some other conservative and hierarchical societies like Japan, gay men will get into hookup culture then often get married to a woman anyway in order to not bring shame to the family. Sexism played a huge role in society creating a situation where women weren't even considered in the thought process of people angry about gays violating gender norms. The focus has historically been directed towards "failed men" who didn't become fathers.

This created solidarity between gay men and anyone else who was gender nonconforming in any way because we were all breaking the same rule in society. In game of thrones there's an expression that all dwarves are bastards in the eyes of their fathers and basically all effeminate men were fags in the eyes of society. Gender bending in the 80s was a clear attack against right wing concepts of gender. It was a rebellion against gender (the social caste system) where many straight people felt liberated to dress and act in ways which were supposed to be reserved for the opposite sex.

In the 90s and 00s the pop culture dress code became far more conservative. At the time i thought this was a good thing because while 80s outfits were proving a good point and were liberating, they did tend to make people look ridiculous. The 90s became "I don't care about my outfit" grunge and the 00s became "perhaps men and women should dress differently because it compliments their bodies differently so I care about my outfit again" sexed clothing. This coincided with a DRAMATIC change in popular perception about gay people.

Keep in mind the long standing solidarity within the gay community surrounding gender nonconformity and now society was starting to shift from extreme disgust to indifference. The simultaneous shift to more conservative views on gendered clothing with society still seeing gays as persecuted created a vacuum where certain people could easily jump in the driver's seat and run the car off the road. Straight with extra steps Cluster-B personality disorders were suddenly viewed as having moral superiority simply by existing and they were rewarded for acting out.

Gays didn't choose to exist suddenly with these people. It was the result of cultural momentum.